What is the relationship between temperature change and mass extinction?
Background
Climate change affects all life on earth. Predicting how a warming climate will affect species on earth is one of the biggest goals for climate researchers today. Despite the importance of this goal, a precise answer to the question of how climate change will affect species in the future is still being sought. One of the key places that scientists look for answers is in the past. Specifically they look to geologic data to provide insight into how past temperature changes and extinction rates have been correlated so that we can make predictions about the effect that our now warming climate may have on species currently living on our planet.
Dataset
This dataset is a subset of the data that were published in a recent scientific paper titled Thresholds of temperature change for mass extinctions. The data are publicly available and were accessed to make this activity. According to the authors of the original study, the paleotemperature data found in this dataset were derived from oxygen isotope, clumped isotope and organic geochemistry data from carbonate fossils. Extinction rates were calculated for marine animals only using data from the Paleobiology Database.
Variables
Age (Mya)- This numeric variable is the estimated time point for a row of data. It is based on the isotope and chemistry data from carbonate fossils.
ΔT (°C)- This numeric variable is the magnitude of change in temperature estimated for a given time span (~6-20 million years). It is reported in degrees Celsius.
R (°C /Myr)- This numeric variable is the rate of change in temperature estimated for a given time span. It is reported as degrees Celsius per million years.
Extinction Rate- This numeric variable is the extinction rate as estimated with the Gap-filler method that is based on analysis of the fossil record of carboniferous marine animals.
Activity
1) Make a graph showing the extinction rate over time as calculated with the methods in this study. Show Age (Mya) on the X-axis and Extinction Rate on the Y-axis. If you wish, you may reverse the X axis to make time chronological from left to right.
2) Based on your graph, describe changes in the extinction rate over the last 450 million years as calculated in this study.
3) Explore the relationship between the magnitude of temperature change and extinction rate. Make a graph and show ΔT (°C) on the X-axis and Extinction Rate on the Y-axis.
4) What do you notice about the trend in the data? Try fitting regression lines to the data. Which regression lines/functions best fit the data? What does this tell you about the relationship between temperature change and the extinction rate.
5) Visualize these data in a different way. Transform the ΔT (°C) data with the absolute value function. Now make a graph with absolute value of ΔT (°C) showing on the X axis and Extinction Rate showing on the Y axis.
6) Compare the graphs you made in questions #s 3 and 5. Which do you prefer for seeing the trend in the data and why?
7) Based on these data and your graphs, what amount of climate change (in degrees Celsius) should humans be concerned with? Use the data as evidence to support your answer.
Additional Resources
Link to the original 2021 paper: